Abstract: A sideview mirror includes a housing having an inner tubular member and an outer tubular member. The housing has a main pipe and a branching pipe extending laterally from a center portion of the main pipe. An object lens system is arranged in a rearward portion of the main pipe, and an eye lens system is arranged in the branching pipe. A blowing device is provided in the forward portion of the main pipe. The main pipe further includes a reflecting member in its center portion to form a predetermined angle with respect to an optical axis of the eye lens system. The blowing device includes a cover plate which has through holes as air apertures and a movable plate having air apertures. The air apertures of the cover plate and the movable plate may be selectively aligned to allow air to enter the mirror. An air guider is provided to guide the entering air to the object lens system and the eye lens system.